Looking through the Little League rule book but somehow missing the rule that I'm looking for.

Minors LL: 5 runs per inning (2.00 - Inning). But where does it describe the unlimited runs in the last inning?

5.07 ... (Minor League: The side is retired when three offensive players are legally put out, or when all players on the roster have batted one time in the half-inning; or when the offensive team scores five (5) runs. (OPTION: The local league board of directors may suspend the five-run rule on the last half-inning for either team.) ...

I think the last inning suspension of the 5 run limit is a bit unfair. Say for example, team A gets to five runs three times with nobody out in the first 5 innings but goes down 1-2-3 in the 6th as they are at the bottom of their lineup. Is it fair that team B who is retired on three outs in the first 5 innings scores say 9 in the sixth to win? It is giving one team more outs than the other.

I think the last inning suspension of the 5 run limit is a bit unfair. Say for example, team A gets to five runs three times with nobody out in the first 5 innings but goes down 1-2-3 in the 6th as they are at the bottom of their lineup. Is it fair that team B who is retired on three outs in the first 5 innings scores say 9 in the sixth to win? It is giving one team more outs than the other.

We used to allow an unlimited 6th inning in our league but after watching some 10-20 run innings by both teams, extending the time of the game by an hour +, we got rid of the local rule.
When a pitcher cant even come close to the strike zone in the 6th inning it becomes real painful, as player, coach, parent and ump.

If minors is for training and not winning, then unlimited 6th innings make even less sense.

It's not that winning is completely unimportant at the minors level, nor is it the main focus of the league. Admittedly, minors is a developmental league (just like LL 'fall ball'). But the object of the game is to win by plating more runs than your opponent.

If you are mathematically eliminated from being able to win the game, you've reduced the game to a practice scrimmage. Guess what happens then? (I know.. I experienced it several times the first year LL went to the 5-run limit!)

When a coach can no longer win or lose a game, he starts putting players where they have had absolutely no previous experience at. This includes the pitcher's mound and behind the plate. I'm all for young kids getting a crack at any and every position they would like to try to play, but they should learn those positions in practice, not in a game.

Do you know how long it takes to walk in 5 runs on 8 walks in one half-inning, factoring in a trip to the backstop for the catcher on almost every pitch? I do. I've lived it several times. And each time it was when a team was beyond the mathematical ability to win or lose a game. There was absolutely no way to get strikes, either. Can't call strikes that bounce in front of the plate or sail over the catcher's head.

So.... keeping the possibility of any team winning all the way up to the very last out is a good thing, and it keeps in the spirit of the saying, "It ain't over until the last out."

Team B wins by scoring more runs using 17 outs than team A did with 9 outs just because they happened to have their best inning in the 6th.

If minors is for training and not winning, then unlimited 6th innings make even less sense.

You said:

Is it fair that team B who is retired on three outs in the first 5 innings - (and nothing like what you just posted).

That's zero runs where I live. Somehow I was to assume your scenario?

The unlimited last inning is to keep playing rather than shutting down due to an inability to score enough. We want the kids playing, not going home early. If you read the book, they can only play until they bat around anyhow - that part of the rule isn't altered. It isn't really unlimited, it's just "more than 5".